Screw-propeller.



A. P. FILIPPI.

SCREW PROPBLLER. I APPLICATION FILED EAL-24, 1911. 1

1,078,270 v Patented N0v .11',1913.

INVENTOR SANV'IOINE renown FILIPPI, F rams TRANCE.-

scmaw-rno- ELLER.

A pplication filed March 24," 1911. Serial No. 616,712

To all whom it may concern:

Be known that I, AN'ronsn 'PADOUE FILIPPI, a citizen of the French Republic, residing at 132 Avenue 'du Maine, Paris, France, have-invented new and useful Improvements in Screw-Propellers, of which the following is a specification.

The present-invention relates to a screw.

propeller with two or more blades.

10 According to this invention the pitch of the blades increases from the boss toward the end and from the leading edgetoward the trailing edge.

Each blade of the screw is combined near the boss .with aplane thatforms a determined angle with the blade.

. found on each of the faces of the blade. The plane arranged on the back face is. intended to contribute to the retention or hold; the

- plane arranged on the front face and on the side of the leading edge is intended to reduce the velocity of the small streams of Water. normal to the propeller by diverting these small streams of water so as to throw them in front of the leading edge. It will .thus be seen that each blade is provided at the bottom, in the front part, with a diverting surface, and at the back part with a retaining surface.

The-purpose intended is to .relieve the I front surface of the propeller and to have as much water as possible on the back surface. i

In the accompanying drawings several views are given illustrating by way of example two different methods of carrying out the present invention.

Figure l is a plan of the front face of a propeller with two blades. Fig. 2 is a plan 40 of the back face. Fig. 3 is a side elevation,

the right hand part of the figure representing the back face, and the left hand part representing the front face of the blades. Fig. 4: is an end elevation of the screw, the direction of rotation of the propeller being toward the left hand side of the figure. Fig. 5 is a section through I-I in Fig. 1, and Fig. 6 a section through IL-II in the same figure. Figs. 7, 8- and 9 are respectively a plan, a side elevation,- and an end elevation illustrating another method of constructing the same propeller. 10 is a diagrammatic This plane is 1 figure showing a plurality of sectional views of the KlGVlCG.

As will be seen from the drawings each blade 1 has on the side of the trailing edge on its front face a plane 2 forming a diverting surface which facilitates the arrival of Specification ofLettersPatent. t t 1 19 the water under the other blade 1'. This central diverting surface, by reducing, as has, been mentioned, the velocity of the small liquid streams, enables the leading edge 3 of the surface 1 to meet and totake support on them. On this back face (Figs. :2 and '5) the" retention surface 4 prevents the small streamsof water which are in this area and which are subjected to less action of the centrifugal force in consequence of their coming nearer to the center, from escaping by the issue edge 5 of the blade '1, and keeps always full of water, the area partially lim-,

ited by the surface of the blade 1 between the end (3 of that blade and the axis 7 of the boss.

The planes of the two blades; intersect each other as shown-by the lines of intersection a-b-a-// which, if the surfaces are planes, may be rcctilineal, but may have any other form according to the nature of the surfaces adopted. Thus, in Figs. 7 8 and 9, the surfaces adopted being approximately parabolic or ellipsoidal, the intersections of,

these surfaces give the curve which is shown in the drawings. It is quite evident that this arrangement of the blades is independent of the angle which they form in relation to one another in any plane whatever, or of the angle which they form with the shaft of the screw. The blade may obviouslyhave any external contour whatever. These means together enable the mean pitch of the screw to be reduced, the screw to'be turned very quickly while assuring the retention of the water on the working surface, and the relieving of the blade on the front surface, the result of which is very great efficiency.

What I claim and desire to secure by'Letters Patent is A screw propeller comprising a plurality of blades, in each of which the pitch increases-from the hub to the end, and from the leading edge to the trailing edge, the front-face of each blade being provided with an incl'ned surface adjacent its trailing edge and adjacent the hub of the propeller, In testimony whereof I haves igned m the rear face of each blade being provided name to this specification in the presence of "10 wlth an inclined surface'adjacent thehub of two subscribing witnesses. the propeller, the planes of said inclined surfaces mtersecting one anotlier and pass- ANTOINE PADOUE FILIPPI' ingthrough the shaftoff "tli e propeller, such Witnesses: 1verting surfaces forming suitable, angles H. CICOXE, with theblades. MIGUEL FEROLO. 

